My problem is when i click on this button very fast :
Extjs does not wait the server to finish the first request so it does not yet receive the success proprety.
Then the second request is an array of items with the item of my first request and the item of my second request.
The item of my fisrt request has been created but extjs does not wait for the success proprety and send item of my first request a second time on my second request.
So the item of my first request is created twice...